Design Scenes, Not Plays!

One of the key tenets of the OSR playstyle is to never railroad the players. They're not there to "play" your fantasy book and make some rolls. They're not to play a Choose Your Own Adventure either. Their actions should have consequences instead of having a Quantum Ogre in every room. I would like to expand this concept a bit further and provide a simple yet elegant solution to avoid this kind of problems.

The first solution is, of course, to not design plots. If you don't have a start and an ending there's nothing to guide your players trough and no need for unkillable NPCs and obligatory encounters. But let's assume we're past this problem. We're now in OSR territory and everyone has his own shiny hexcrawl with stuff to do, lots of dungeons and player agency. Are we free from any kind of problems? No.

The problems arise when you, the DM, have prepped a single encounter (let it be a trap, a monster or a whole dungeon) and treated it like a meta-plot. An encounter doesn't have a beginning and an end, it only must have a beginning while the ending is optional. Your players shouldn't be forced to beat the Crimson Spider just because they have encountered it, and they shouldn't be forced to go to the Crypt Of The Black Throne just because you designed it.

You should be a prop designer in your own world, responsible for scenes (and outcomes in due time). Whenever you design a problem, don't design a solution for it or you will be tempted to impose it on the players. If you're designing a play you're forming a web of connected encounters that flow one into another as you have designed them, even if the play is non linear. If you're only designing scenes it really doesn't matter what the outcome of one scene will be.

Let your players surprise you, and if they want to avoid the Quantum Ogre room just by digging trough walls, well, let them.